[PATCH v1 4/4] selftests/bpf: Add netpoll setup basic tests

[Mahe Tardy <mahe.tardy@gmail.com>]

Add a pair of BPF progs, netpoll_release and netpoll_acquire to test
that the respective bpf_netpoll_release and bpf_netpoll_acquire behave
as expected and that the verifier has been configured to catch
unreleased references.

Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com>
---
 .../selftests/bpf/prog_tests/netpoll.c        | 23 +++++++++
 .../selftests/bpf/progs/netpoll_basic.c       | 47 +++++++++++++++++++
 2 files changed, 70 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/netpoll_basic.c

diff --git a/tools/testing/selftests/bpf/prog_tests/netpoll.c b/tools/testing/selftests/bpf/prog_tests/netpoll.c
index eac0378c426a..daea1068a739 100644
--- a/tools/testing/selftests/bpf/prog_tests/netpoll.c
+++ b/tools/testing/selftests/bpf/prog_tests/netpoll.c
@@ -7,15 +7,38 @@
 #include "test_progs.h"
 #include "network_helpers.h"
 #include "netpoll_sanity.skel.h"
+#include "netpoll_basic.skel.h"

 #define NS_TEST "netpoll_sanity_ns"
 #define NS_TEST_V6 "netpoll_sanity_ns_v6"
+#define NS_BASIC_TEST "netpoll_basic_ns"
 #define DUMMY_DEV "dummy0"
 #define DUMMY_IP "10.0.0.1"
 #define REMOTE_IP "10.0.0.2"
 #define DUMMY_IP6 "fd00::1"
 #define REMOTE_IP6 "fd00::2"

+void test_netpoll_basic(void)
+{
+	struct nstoken *nstoken = NULL;
+
+	SYS(fail, "ip netns add %s", NS_BASIC_TEST);
+	SYS(fail, "ip -net %s link add %s type dummy", NS_BASIC_TEST, DUMMY_DEV);
+	SYS(fail, "ip -net %s addr add %s/24 dev %s", NS_BASIC_TEST, DUMMY_IP, DUMMY_DEV);
+	SYS(fail, "ip -net %s link set %s up", NS_BASIC_TEST, DUMMY_DEV);
+
+	nstoken = open_netns(NS_BASIC_TEST);
+	if (!ASSERT_OK_PTR(nstoken, "open_netns"))
+		goto fail;
+
+	RUN_TESTS(netpoll_basic);
+
+fail:
+	if (nstoken)
+		close_netns(nstoken);
+	SYS_NOFAIL("ip netns del %s &> /dev/null", NS_BASIC_TEST);
+}
+
 static void run_netpoll_test(const char *ns_name, const char *local_ip,
 			      const char *remote_ip, bool ipv6)
 {
diff --git a/tools/testing/selftests/bpf/progs/netpoll_basic.c b/tools/testing/selftests/bpf/progs/netpoll_basic.c
new file mode 100644
index 000000000000..2650e1e5410a
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/netpoll_basic.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2026 Isovalent. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+#include "errno.h"
+
+SEC("syscall")
+__success __retval(0)
+int netpoll_release(void *ctx)
+{
+	struct bpf_netpoll_opts opts = { .dev_name = "dummy0" };
+	struct bpf_netpoll *bnp;
+	int err = 0;
+
+	bnp = bpf_netpoll_create(&opts, sizeof(opts), &err);
+	if (!bnp)
+		return err;
+
+	bpf_netpoll_release(bnp);
+
+	return 0;
+}
+
+SEC("syscall")
+__failure __msg("Unreleased reference")
+int netpoll_acquire(void *ctx)
+{
+	struct bpf_netpoll_opts opts = { .dev_name = "dummy0" };
+	struct bpf_netpoll *bnp;
+	int err = 0;
+
+	bnp = bpf_netpoll_create(&opts, sizeof(opts), &err);
+	if (!bnp)
+		return err;
+
+	bnp = bpf_netpoll_acquire(bnp);
+	if (!bnp)
+		return -EINVAL;
+
+	bpf_netpoll_release(bnp);
+
+	return 0;
+}
+
+char __license[] SEC("license") = "GPL";
--
2.34.1